Ranked in these QuestionsQuestion Ranking
Pro Separates concerns
Rack is great at separating the different stages of a request, allowing developers to easily follow separation of concerns, a key goal for any well designed software.
Pro Great ecosystem
There's a great community and ecosystem built around Rack. You can easily find pre-built components to do almost anything you are planning to.
Con Not great for large complex applications
Rack is a very bare-bones middleware useful for easily creating REST APIs without too many bells and whistles. As such, it may prove useless to build a complex web application that relies on the backend for most of its operations with Rack.